Juvenile dermatomyositis is an autoimmune disease that affects children. Symptoms include skin rashes and swelling and weakening muscles. Treatment includes corticosteroids or biologic agents.
JDM is an autoimmune disease that affects muscle, skin and small blood vessels in children. The body's immune system attacks its own healthy muscle, skin and blood vessel tissues because it mistakenly sees them as invaders. The primary symptoms are muscle weakness and skin rashes due to inflammation from an overactive immune system.
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JDM is a rare autoimmune disease with approximately 2-4 children per one million children being diagnosed each year in the United States. The disease presents more commonly in girls than boys and usually occurs between the ages of 2 and 15.
The cause of JDM is not known. Researchers believe it may be a result of the body’s abnormal immune system response to environmental triggers (eg, a virus) in children with a genetic predisposition to having an overactive immune system. Even after the trigger is gone, the immune system continues to fight and ends up attacking the body itself.
The main symptoms of juvenile dermatomyositis are muscle weakness and skin rashes. This is caused by inflammation in the small blood vessels (vasculitis) in skin and muscle and also by inflammation of the muscle cells. Other symptoms may include:
Due to these symptoms, the child may not feel like participating in normal childhood activities. Sometimes the child may even be accused of being lazy.
Diagnosing JDM can be difficult because it is a relatively rare disease. In making a diagnosis, the doctor will gather information from the medical history, the physical examination and testing. Testing may include:
Treatment of JDM depends on how severe the disease is. The goals of treatment are to: control inflammation and prevent tissue damage; improve muscle strength; relieve pain; prevent other symptoms; and help the child and family live with the disease.
Some common medications include:
The side effects of medications for JDM include the following:
Corticosteroids can cause weakened bones (osteoporosis), cataracts, upset stomach, weight gain, agitation, mood changes, and changes in blood sugar. For these reasons, corticosteroids are used only used when necessary, and the dosage is reduced gradually over time.
Immunosuppressants can cause nausea, fatigue, abdominal pain, and mild hair loss. Close monitoring is performed to prevent side effects to the kidney, liver, and blood counts. Immunosuppressants lower the body's immune system, increasing one's risk of getting an infection.
Intravenous immune globulin (IVIG) may have acute side effects such as backache, headache, and fever. Intravenous immune globulin is expensive and requires repeated doses every 3-4 weeks in general.
Hydroxychloroquine may interfere with color vision over a long period of usage (very rare). The child should visit an eye doctor yearly while taking this drug.
Biologic agents also increase one's risk of infection. The treatments are expensive and are not always covered by insurance.
At this time, because the cause of JDM is unknown, there is no method to prevent development of the condition.
Patients usually respond well to treatment. Gradual improvement over a few months is typical. Most patients recover completely (remission), meaning that they no longer show signs of active disease or flare-ups. Yet there is a group of patients for whom treatment may not be 100 percent effective.
Patients who remain with longer periods of active disease are at higher risk of complications, such as permanent muscle weakness and stiffness, calcinosis (hard nodule deposit under skin) or cardiopulmonary issues.
Children with JDM should live life as normally as possible. They should attend school, play sports, and participate in extra-curricular and family activities. In general, there is no specific limitation regarding physical activity if the children want to do things, as long as the activity is safe. Exercise does not harm JDM. In fact, it helps prevent deconditioning, increases muscle strength and muscle endurance, and boosts energy.
UV light from the sun can trigger a disease flare, so your child should avoid sun exposure. Outdoor activity is possible, but your child needs to apply sunscreen diligently and wear protective clothing.
There is no special diet that has been shown to be effective for JDM, or a diet that makes it worse. Therefore, children with JDM should eat a standard well-balanced healthy diet.
The Cure JM Foundation is a non-profit foundation that aims to increase awareness of juvenile myositis, offers resources for patients and families, and funds research. More information can be found at: http://www.curejm.org/index.php.
Last reviewed by a Cleveland Clinic medical professional on 01/18/2019.
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